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Open Access Publications from the University of California

Scholarly Works (2 results)

  • Thesis
  • Peer Reviewed
UC Irvine Electronic Theses and Dissertations (2014)

The atomic force microscope (AFM) has become an extremely powerful tool for biological and cell studies. Modified AFM probes have been designed to inject biomolecules (DNA, proteins, etc.) into living cells or extract target biomolecules expressed inside the cells. However, the need for statistically significant sample sizes makes data collection an extremely lengthy process. A complementary microfluidic device can decrease data collection time by flowing cells passed the probe tip and immobilizing them while the probe investigates or manipulates the cell. Microfluidic devices generally do not permit physical access to channels and the ability to add or remove material is restricted to designated inlets and outlets, endpoints in microfluidic devices. True open-access microfluidics suffers from low pressure and flow rate limitations and an inability to integrate multiple modules. This research demonstrates a microfluidic device which can encapsulate cells within droplets, immobilize droplets, and release droplets to collect and analyze. Sealing the device with a thin film of PDMS provides the liberty for a probe to inject, extract, or inspect material from any portion of the channels while providing a barrier to confine the fluid to within the channels during device operation.

    Cover page: A Complementary Microfluidic Device for Droplet-Based Single Cell Studies with an AFM SystemCreative Commons 'BY' version 4.0 license
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2018)

    Background

    Human immunodeficiency virus (HIV) penetrates the brain in early infection. We used neuroimaging to longitudinally examine the impact of HIV and combination antiretroviral therapy (cART) on the brain in treated and untreated HIV-infected participants, starting in primary HIV infection (PHI).

    Methods

    Sixty-five participants, enrolled during PHI, underwent longitudinal magnetic resonance imaging, 30 of whom commenced cART during follow-up. Cross-sectional data from 16 patients with chronic HIV infection (CHI) and 19 HIV-uninfected participants were included for comparison. Brain volume and cortical thickness were estimated using tensor-based morphometry and cortical modeling, respectively. Mixed-effects models longitudinally mapped structural brain changes before and after cART. The relationship between brain morphometry estimates and blood and cerebrospinal fluid (CSF) biomarkers were also tested. Region-of-interest analyses were performed to compare brain morphometry estimates between the groups.

    Results

    Prior to cART, longer duration of untreated infection in PHI correlated with volume loss in the thalamus, caudate, and cerebellum, and with cortical thinning in the frontal and temporal lobes and cingulate cortex. After cART, no further volume loss was observed. However, small increases of cortical thickness in the frontal and temporal lobe correlated with longer cART duration. No correlations were observed with blood or CSF measures. The PHI group did not have different brain morphometric measures compared to the HIV-uninfected group, but had larger volumes in the thalamus, caudate, putamen, and cortical gray matter compared with CHI participants.

    Conclusions

    Subcortical atrophy and cortical thinning occur during untreated infection but may be arrested by cART. These findings emphasize the importance of early cART.
      Cover page: Longitudinal Trajectories of Brain Volume and Cortical Thickness in Treated and Untreated Primary Human Immunodeficiency Virus Infection
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